Liquid crystal polyester resin composition and molded body

ABSTRACT

A liquid crystal polyester resin composition containing 100 parts by mass of a liquid crystal polyester resin; and at least 5 parts by mass and at most 100 parts by mass of glass components; wherein the glass components contain glass fibers having a length of more than 50 μm and glass fine powders having a length of at least 4 μm and at most 50 μm; the number-average fiber length of the glass fibers is at least 200 μm and at most 400 μm; and the content of the fine powders is at least 20% and at most 95% relative to a total number of the glass components.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. § 371 ofInternational Application No. PCT/JP2018/042981, filed on Nov. 21, 2018,which claims the benefit of Japanese Application No. 2017-227144, filedon Nov. 27, 2017, the entire contents of each are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to a liquid crystal polyester resincomposition, and a molded body.

Priority is claimed on Japanese Patent Application No. 2017-227144,filed Nov. 27, 2017, the disclosure of which is incorporated herein byreference.

BACKGROUND ART

Liquid crystal polyester resins have very excellent melt flowability,and depending on their structure, may have thermal deformationresistance to 300° C. or higher. Taking advantage of these properties,liquid crystal polyester resins are used in molded bodies for uses suchas electronic components, as well as office appliances, audiovisualcomponents, heat-resistant tableware and the like.

In the electronic component field, advances are being made inminiaturization and precision, and molded bodies obtained by usingliquid crystal polyester resins are becoming extremely thin. Thethinning of molded bodies is causing problems such as decreased strengthin the molded bodies, the controlling of anisotropy in the liquidcrystal polyester resins and the like. In order to solve these problems,liquid crystal polyester resin compositions in which fibrous fillers areblended with liquid crystal polyester resins are being used (forexample, Patent Documents 1 to 3).

CITATION LIST Patent Documents

[Patent Document 1] JP H6-240115 A

[Patent Document 2] JP 2009-191088 A

[Patent Document 3] WO 2012/090410

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

For the purposes of protecting the environment and cutting costs byreducing waste, recycling methods that involve grinding molded bodiessuch as runners and sprues that are generated during injection molding,and reusing the ground molded bodies as raw materials in the productionof molded bodies, or mixing some of the ground molded bodies with rawmaterials that have not been used in the production of molded bodies,and reusing the mixtures as raw materials in the production of moldedbodies, have started to be considered.

Hereinafter, in the present description, the grinding of molded bodiesand their regeneration as raw materials for use in the production ofmolded bodies will be referred to as “regrinding” and the resultingground matter will be referred to as “reground material”. In contrasttherewith, raw materials that have not been used in the production ofmolded bodies will be referred to as “virgin material”.

Reground material is known to have physical properties that aregenerally inferior in comparison to those of virgin material. Regroundmaterial has a more extensive thermal history than virgin material does.For this reason, it is thought that degradation of the resin due to heatlowers the mechanical strength of molded bodies formed by using regroundmaterial. Additionally, reground material is produced by grinding. Forthis reason, the physical destruction of fillers is thought to lower themechanical strength of molded bodies formed by using reground material.

Thus, in order to effectively utilize reground material, there has beena demand for a liquid crystal polyester resin composition (virginmaterial) wherein the mechanical strength of molded bodies usingreground material does not easily become lower than the mechanicalstrength of molded bodies using virgin material and can be kept within arange allowing use in molded bodies.

The resin compositions described in Patent Documents 1 to 3 do notnecessarily have high mechanical strength retention rates when reground.

In the present description, “mechanical strength” refers to the tensilestrength and the Izod impact strength. Additionally, the “mechanicalstrength retention rate” is a value calculated as the physical value ofthe mechanical strength of a molded body formed by using regroundmaterial relative to the physical value of the mechanical strength of amolded body formed by using virgin material.

The present invention was made in consideration of these circumstances,and has the purpose of providing a liquid crystal polyester resincomposition and a molded body having a high mechanical strengthretention rate when reground.

Means to Solve the Problems

In order to solve the above-mentioned problem, an embodiment of thepresent invention provides a liquid crystal polyester resin compositioncomprising 100 parts by mass of a liquid crystal polyester resin; and atleast 5 parts by mass and at most 100 parts by mass of glass components;wherein the glass components contain glass fibers having a length ofmore than 50 μm and glass fine powders having a length of at least 4 μmand at most 50 μm; the number-average fiber length of the glass fibersis at least 200 μm and at most 400 μm; and the content of the finepowders is at least 20% and at most 95% relative to a total number ofthe glass components.

In one embodiment of the present invention, the fine powders may becomposed of glass first fine powders having a length of at least 4 μmand at most 40 μm, and second fine powders having a length of more than40 μm and at most 50 μm; and at least 40% and at most 90% of the firstfine powders may be contained relative to the total number of the glasscomponents.

In one embodiment of the present invention, the content of the finepowders may be at least 70% and at most 90% relative to the total numberof the glass components.

In one embodiment of the present invention, the fine powders may have adiameter of at least 9 μm and at most 12 μm, and the fine powders mayhave an aspect ratio of at least 0.3 and at most 5.6.

In one embodiment of the present invention, the liquid crystal polyesterresin may contain repeat units represented by formulas (1) to (3) below:—O—Ar¹—CO—  (1)—CO—Ar²—CO—  (2)—X—Ar³—Y—  (3)wherein

Ar¹ represents a phenylene group, a naphthylene group or a biphenylylenegroup;

Ar² and Ar³ represent, independently of each other, a phenylene group, anaphthylene group, a biphenylylene group or a group represented byformula (4) below;

X and Y represent, independently of each other, an oxygen atom or animino group (—NH—); and

at least one hydrogen atom in the group represented by Ar¹, Ar² or Ar³may, independently of each other, be substituted by a halogen atom, analkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20carbon atoms;—Ar⁴—Z—Ar⁵—  (4)wherein

Ar⁴ and Ar⁵ represent, independently of each other, a phenylene group ora naphthylene group; Z represents an oxygen atom, a sulfur atom, acarbonyl group, a sulfonyl group or an alkylidene group having 1 to 10carbon atoms; and

at least one hydrogen atom in the group represented by Ar⁴ or Ar⁵ may,independently of each other, be substituted by a halogen atom, an alkylgroup having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbonatoms.

In one embodiment of the present invention, Ar¹ may be a 1,4-phenylenegroup, Ar² may be a 1,4-phenylene group and a 1,3-phenylene group, Ar³may be a biphenylylene group, and X and Y may each be oxygen atoms.

In one embodiment of the present invention, a molar ratio (3)/(1)between repeating units represented by formula (1) and repeating unitsrepresented by formula (3) may be at least 0.2 and at most 1.0; and amolar ratio (2)/(3) between repeating units represented by formula (3)and repeating units represented by formula (2) may be at least 0.9 andat most 1.1.

In one embodiment of the present invention, a molar ratio y/x betweenrepeating units represented by formula (2) may be greater than 0 and atmost 1, wherein x represents a molar content of repeating units in whichAr² is a 1,4-phenylene group; and y represents a molar content ofrepeating units in which Ar² is a 1,3-phenylene group.

In one embodiment of the present invention, the liquid crystal polyesterresin may contain a first liquid crystal polyester resin and a secondliquid crystal polyester resin, and α/β may be at least 0.1 and at most0.6, wherein α represents the molar ratio y/x in the first liquidcrystal polyester resin; and β represents the molar ratio y/x in thesecond liquid crystal polyester resin.

An embodiment of the present invention provides a molded body having, asthe forming material thereof, a liquid crystal polyester resincomposition as mentioned above.

In other words, the present invention includes the embodiments below.

[1] A liquid crystal polyester resin composition comprising:

100 parts by mass of a liquid crystal polyester resin; and

at least 5 parts by mass and at most 100 parts by mass of glasscomponents; wherein

the glass components contain glass fibers having a length of more than50 μm and glass fine powders having a length of at least 4 μm and atmost 50 μm;

the number-average fiber length of the glass fibers is at least 200 μmand at most 400 μm; and

the content of the fine powders is at least 20% and at most 95% relativeto a total number of the glass components.

[2] The liquid crystal polyester resin composition according to [1],wherein:

the fine powders are composed of first fine powders having a length ofat least 4 μm and at most 40 μm, and second fine powders having a lengthof more than 40 μm and at most 50 μm; and

the content of the first fine powders is at least 40% and less than 90%relative to the total number of the glass components.

[3] The liquid crystal polyester resin composition according to [1] or[2], wherein the content of the fine powders is at least 70% and at most90% relative to the total number of the glass components.

[4] The liquid crystal polyester resin composition according to any oneof [1] to [3], wherein the liquid crystal polyester resin containsrepeating units represented by formulas (1) to (3) below:—O—Ar¹—CO—  (1)—CO—Ar²—CO—  (2)—X—Ar³—Y—  (3)wherein

Ar¹ represents a phenylene group, a naphthylene group or a biphenylylenegroup;

Ar² and Ar³ represent, independently of each other, a phenylene group, anaphthylene group, a biphenylylene group or a group represented byformula (4) below;

X and Y represent, independently of each other, an oxygen atom or animino group (—NH—); and

at least one hydrogen atom in the group represented by Ar¹, Ar² or Ar³may, each independently, be substituted by a halogen atom, an alkylgroup having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbonatoms;—Ar⁴—Z—Ar⁵—  (4)wherein

Ar⁴ and Ar⁵ represent, independently of each other, a phenylene group ora naphthylene group; Z represents an oxygen atom, a sulfur atom, acarbonyl group, a sulfonyl group or an alkylidene group having 1 to 10carbon atoms; and

at least one hydrogen atom in the group represented by Ar⁴ or Ar⁵ may,each independently, be substituted by a halogen atom, an alkyl grouphaving 1 to 10 carbon atoms or an aryl group having 6 to 20 carbonatoms.

[5] The liquid crystal polyester resin composition according to [4],wherein Ar¹ is a 1,4-phenylene group, Ar² is a 1,4-phenylene group and a1,3-phenylene group, Ar³ is a biphenylylene group, and X and Y are eachoxygen atoms.

[6] The liquid crystal polyester resin composition according to [4] or[5], wherein:

a molar ratio (3)/(1) between repeating units represented by formula (1)and repeating units represented by formula (3) is at least 0.2 and atmost 1.0; and

a molar ratio (2)/(3) between repeating units represented by formula (3)and repeating units represented by formula (2) is at least 0.9 and atmost 1.1.

[7] The liquid crystal polyester resin composition according to any oneof [4] to [6], wherein a molar ratio y/x between repeating unitsrepresented by formula (2) is greater than 0 and at most 1, wherein:

x represents a molar content of repeating units in which Ar² is a1,4-phenylene group; and

y represents a molar content of repeating units in which Ar² is a1,3-phenylene group.

[8] The liquid crystal polyester resin composition according to [7],wherein the liquid crystal polyester resin contains a first liquidcrystal polyester resin and a second liquid crystal polyester resin, andα/β is at least 0.1 and at most 0.6, wherein:

α represents the molar ratio y/x in the first liquid crystal polyesterresin; and

β represents the molar ratio y′/x′ in the second liquid crystalpolyester resin.

[9] A molded body formed from the liquid crystal polyester resincomposition according to any one of [1] to [8].

Effects of the Invention

According to an embodiment of the present invention, a liquid crystalpolyester resin composition having a high mechanical strength retentionrate when reground, and a molded body, are provided.

EMBODIMENTS FOR CARRYING OUT THE INVENTION Liquid Crystal PolyesterResin Composition

The liquid crystal polyester resin composition in the present embodimentcontains a liquid crystal polyester resin and glass components.

Liquid Crystal Polyester Resin

Typical examples of liquid crystal polyester resins according to thepresent embodiment include polymers obtained by condensationpolymerization (polycondensation) of an aromatic hydroxycarboxylic acid,an aromatic dicarboxylic acid, and at least one compound selected fromthe group consisting of an aromatic diol, an aromatic hydroxylamine andan aromatic diamine; polymers obtained by polymerizing multiple types ofaromatic hydroxycarboxylic acids; polymers obtained by polymerizing anaromatic dicarboxylic acid and at least one compound selected from thegroup consisting of an aromatic diol, an aromatic hydroxylamine and anaromatic diamine; and polymers obtained by polymerizing a polyester suchas polyethylene terephthalate and an aromatic hydroxycarboxylic acid.

Among the above, polymers obtained by condensation polymerization(polycondensation) of an aromatic hydroxycarboxylic acid, an aromaticdicarboxylic acid, and at least one compound selected from the groupconsisting of an aromatic diol, an aromatic hydroxylamine and anaromatic diamine are preferred.

In this case, the aromatic hydroxycarboxylic acid, the aromaticdicarboxylic acid, the aromatic diol, the aromatic hydroxylamine and thearomatic diamine may, independently of each other, be replaced partiallyor entirely with a polymerizable ester-forming derivative thereof.

Examples of polymerizable derivatives of compounds having a carboxygroup, such as an aromatic hydroxycarboxylic acid and an aromaticdicarboxylic acid, include esters, acid halides and acid anhydrides.Examples of the above-mentioned esters include compounds obtained byconverting a carboxy group to an alkoxycarbonyl group or anaryloxycarbonyl group. Examples of the above-mentioned acid halidesinclude compounds obtained by converting a carboxy group to a haloformylgroup. Examples of the above-mentioned acid anhydrides include compoundsobtained by converting a carboxy group to an acyloxycarbonyl group.

Examples of polymerizable derivatives of compounds having an aminogroup, such as an aromatic hydroxylamine and an aromatic diamine,include compounds obtained by acylating an amino group and converting itto an acylamino group (i.e., amino group acylates).

Among the indicated examples of polymerizable derivatives, the rawmaterial monomer in the liquid crystal polyester resin is preferably anacylate obtained by acylating an aromatic hydroxycarboxylic acid and anaromatic diol.

The liquid crystal polyester resin according to the present embodimentpreferably has repeating units represented by formula (1) below(hereinafter sometimes referred to as “repeating units (1)”).Additionally, the liquid crystal polyester resin more preferably has therepeating units (1), repeating units represented by formula (2) below(hereinafter sometimes referred to as “repeating units (2)”) andrepeating units represented by formula (3) below (hereinafter sometimesreferred to as “repeating units (3)”).—O—Ar¹—CO—  (1)—CO—Ar²—CO—  (2)—X—Ar³—Y—  (3)

In formulas (1) to (3), Ar¹ represents a phenylene group, a naphthylenegroup or a biphenylylene group.

Ar² and Ar³ represent, independently of each other, a phenylene group, anaphthylene group, a biphenylylene group or a group represented byformula (4) below. X and Y represent, independently of each other, anoxygen atom or an imino group (—NH—).

At least one hydrogen atom in the group represented by Ar¹, Ar² or Ar³may, each independently, be substituted by a halogen atom, an alkylgroup having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbonatoms.—Ar⁴—Z—Ar⁵—  (4)

In formula (4), Ar⁴ and Ar⁵ represent, independently of each other, aphenylene group or a naphthylene group. Z represents an oxygen atom, asulfur atom, a carbonyl group, a sulfonyl group or an alkylidene grouphaving 1 to 10 carbon atoms.

At least one hydrogen atom in the group represented by Ar⁴ or Ar⁵ may,each independently, be substituted by a halogen atom, an alkyl grouphaving 1 to 10 carbon atoms or an aryl group having 6 to 20 carbonatoms.

Examples of halogen atoms that can be substituted for a hydrogen atominclude a fluorine atom, a chlorine atom, a bromine atom and an iodineatom.

Examples of alkyl groups having 1 to 10 carbon atoms that can besubstituted for a hydrogen atom include a methyl group, an ethyl group,a 1-propyl group, an isopropyl group, a 1-butyl group, an isobutylgroup, a sec-butyl group, a tert-butyl group, a 1-hexyl group, a2-ethylhexyl group, a 1-octyl group and a 1-decyl group.

Examples of aryl groups having 6 to 20 carbon atoms that can besubstituted for a hydrogen atom include a monocyclic aromatic group suchas a phenyl group, an ortho-tolyl group, a meta-tolyl group, apara-tolyl group or the like, or a condensed-ring aromatic group such asa 1-naphthyl group or a 2-naphthyl group.

When at least one hydrogen atom in the group represented by Ar¹, Ar²,Ar³, Ar⁴ or Ar⁵ is substituted with the above-mentioned substituentgroups, the number of substituent groups is preferably one or two,independently of each other, for every group represented by Ar¹, Ar²,Ar³, Ar⁴ or Ar⁵. Additionally, it is more preferable for there to be onesubstituent group in every group represented by Ar¹, Ar², Ar³, Ar⁴ orAr⁵.

Examples of the alkylidene groups having 1 to 10 carbon atoms include amethylene group, an ethylidene group, an isopropylidene group, a1-butylidene group and a 2-ethylhexylidene group.

The repeating units (1) are repeating units derived from a prescribedaromatic hydroxycarboxylic acid.

In the present description, “derived” means that the chemical structureis changed for the polymerization of the raw material monomers, while noother structural changes occur.

Examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoicacid, meta-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid,2-hydroxy-3-naphthoic acid, 1-hydroxy-5-naphthoic acid,4-hydroxy-4′-carboxydiphenyl ether, and aromatic hydroxycarboxylic acidsin which some of the hydrogen atoms in the aromatic rings in thesearomatic hydroxycarboxylic acids are substituted with substituent groupsselected from the group consisting of alkyl groups, aryl groups andhalogen atoms.

In the production of the liquid crystal polyester resin, it is possibleto use a single aromatic hydroxycarboxylic acid or to use a combinationof two or more types.

The repeating units (1) are preferably units in which Ar¹ is a1,4-phenylene group (for example, repeating units derived from4-hydroxybenzoic acid) and units in which Ar¹ is a 2,6-naphthylene group(for example, repeating units derived from 6-hydroxy-2-naphthoic acid),among which units in which Ar¹ is a 1,4-phenylene group are morepreferable.

The repeating units (2) are repeating units derived from a prescribedaromatic dicarboxylic acid.

Examples of the aromatic dicarboxylic acid include terephthalic acid,isophthalic acid, biphenyl-4,4′-dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenyl ether-4,4′-dicarboxyclic acid, diphenylthioether-4,4′-dicarboxyclic acid, and aromatic dicarboxylic acids inwhich some of the hydrogen atoms in the aromatic rings in these aromaticdicarboxylic acids are substituted with substituent groups selected fromthe group consisting of alkyl groups, aryl groups and halogen atoms.

In the production of the liquid crystal polyester resin, it is possibleto use a single aromatic dicarboxylic acid or to use a combination oftwo or more types.

The repeating units (2) are preferably units in which Ar² is a1,4-phenylene group (for example, repeating units derived fromterephthalic acid), units in which Ar² is a 1,3-phenylene group (forexample, repeating units derived from isophthalic acid), units in whichAr² is a 2,6-naphthylene group (for example, repeating units derivedfrom 2,6-naphthalene dicarboxylic acid), and units in which Ar² is adiphenyl ether-4,4′-diyl group (for example, repeating units derivedfrom diphenyl ether-4,4′-dicarboxylic acid), among which units in whichAr² is a 1,4-phenylene group and units in which Ar² is a 1,3-phenylenegroup are more preferable.

The repeating units (3) are repeating units derived from a prescribedaromatic diol, aromatic hydroxylamine or aromatic diamine.

Examples of aromatic diols, aromatic hydroxylamines or aromatic diaminesinclude 4,4′-dihydroxybiphenyl, hydroquinone, resorcinol,4,4′-dihydroxydiphenyl ketone, 4,4′-dihydroxydiphenyl ether,bis(4-hydroxyphenyl)methane, 1,2-bis(4-hydroxyphenyl)ethane,4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxydiphenyl thioether,2,6-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 4-aminophenol,1,4-phenylenediamine, 4-amino-4′-hydroxybiphenyl and4,4′-diaminobiphenyl.

In the production of the liquid crystal polyester resin, it is possibleto use a single aromatic diol, aromatic hydroxylamine or aromaticdiamine, or to use a combination of two or more types.

The repeating units (3) are preferably units in which Ar³ is a1,4-phenylene group (for example, repeating units derived fromhydroquinone, 4-aminophenol or 1,4-phenylenediamine), and units in whichAr³ is a 4,4′-biphenylylene group (for example, repeating units derivedfrom 4,4′-dihydroxybiphenyl, 4-amino-4′-hydroxybiphenyl or4,4′-diaminobiphenyl), among which units in which Ar³ is a4,4′-biphenylylene group are more preferable.

The repeating units (3) are preferably units in which X and Y are bothoxygen atoms.

When the molded body obtained from the liquid crystal polyester resincomposition in the present embodiment is required to have particularlygood heat resistance and thermal stability, the repeating units (1) to(3) preferably have fewer substituent groups. Additionally, when themolded body obtained from the liquid crystal polyester resin compositionin the present embodiment is required to have particularly good heatresistance and thermal stability, there are preferably no substituentgroups (for example, alkyl groups) that are susceptible to heat.

In the present embodiment, the heat resistance of the molded body refersto the property in which the resin that is the material forming themolded body does not easily soften in high-temperature environments. Inthe present embodiment, the heat resistance of the molded body can bemade clearer by measuring the load deflection temperature of the resin.The load deflection temperature in the present embodiment is measuredwith a load of 1.82 MPA in accordance with ASTM D648. The higher theload deflection temperature of a resin measured in this way, the higherthe heat resistance of the molded body can be considered to be.

Additionally, in the present embodiment, the thermal stability of themolded body refers to the property in which the resin does not tend todecompose or degrade when the molded body is held at the temperature atwhich the resin is molded (i.e., the melting temperature).

Next, regarding liquid crystal polyester resins that are particularlypreferable for utilization in the present embodiment, combinations ofrepeating units thereof will be explained in detail based on theexamples of repeating units mentioned above.

Specific examples of liquid crystal polyester resins that are preferablein the present embodiment include, for example, resins comprisingrepeating units derived from the monomers mentioned below.

(a) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid copolymer

(b) 4-hydroxybenzoic acid/terephthalic acid/4,4′-dihydroxybi phenylcopolymer

(c) 4-hydroxybenzoic acid/terephthalic acid/isophthalicacid/4,4′-dihydroxybiphenyl copolymer

(d) 4-hydroxybenzoic acid/terephthalic acid/isophthalicacid/4,4′-dihydroxybiphenyl/hydroquinone copolymer

(e) 4-hydroxybenzoic acid/terephthalic acid/hydroquinone copolymer

(f) 2-hydroxy-6-naphthoic acid/terephthalic acid/hydroquinone copolymer

(g) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/terephthalicacid/4,4′-dihydroxybiphenyl copolymer

(h) 2-hydroxy-6-naphthoic acid/terephthalic acid/4,4′-dihydroxybiphenylcopolymer

(i) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/terephthalicacid/hydroquinone copolymer

(j) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/terephthalicacid/hydroquinone/4,4′-dihydroxybiphenyl copolymer

(k) 4-hydroxybenzoic acid/2,6-naphthalene dicarboxylicacid/4,4′-dihydroxybiphenyl copolymer

(l) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylicacid/hydroquinone copolymer

(m) 4-hydroxybenzoic acid/2,6-naphthalene dicarboxylic acid/hydroquinonecopolymer

(n) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/2,6-naphthalenedicarboxylic acid/hydroquinone copolymer

(o) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylicacid/hydroquinone/4,4′-dihydroxybiphenyl copolymer

(p) 4-hydroxybenzoic acid/terephthalic acid/4-aminophenol copolymer

(q) 2-hydroxy-6-naphthoic acid/terephthalic acid/4-aminophenol copolymer

(r) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/terephthalicacid/4-aminophenol copolymer

(s) 4-hydroxybenzoic acid/terephthalicacid/4,4′-dihydroxybiphenyl/4-aminophenol copolymer

(t) 4-hydroxybenzoic acid/terephthalic acid/ethylene glycol copolymer

(u) 4-hydroxybenzoic acid/terephthalicacid/4,4′-dihydroxybiphenyl/ethylene glycol copolymer

(v) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/terephthalicacid/ethylene glycol copolymer

(w) 4-hydroxybenzoic acid/2-hydroxy-6-naphthoic acid/terephthalicacid/4,4′-dihydroxybiphenyl/ethylene glycol copolymer

(x) 4-hydroxybenzoic acid/terephthalic acid/2,6-naphthalene dicarboxylicacid/4,4′-dihydroxybiphenyl copolymer

Among the aforementioned examples, (b) and (c) are preferable, and (c)is more preferable. In other words, it is more preferable that Ar¹ is a1,4-phenylene group, Ar² is a 1,4-phenylene group and a 1,3-phenylenegroup, Ar³ is a biphenylylene group, and X and Y are both oxygen atoms.

The repeating unit (1) content in the liquid crystal polyester resin,relative to the total amount of all repeating units constituting theliquid crystal polyester resin, is preferably at least 30 mol %, morepreferably at least 30 mol % and at most 80 mol %, even more preferablyat least 30 mol % and at most 70 mol %, and particularly preferably atleast 35 mol % and at most 65 mol %. The total amount of all repeatingunits constituting the liquid crystal polyester resin is a valueobtained by dividing the masses of the respective repeating unitsconstituting the liquid crystal polyester resin by the formula weightsof those repeating units to determine the substance-quantity equivalentamounts (moles) of the repeating units, and taking the sum thereof.

If the repeating unit (1) content in the liquid crystal polyester resinis at least 30 mol %, then the heat resistance and hardness of themolded bodies obtained by the liquid crystal polyester resin compositionof the present embodiment can be easily improved. Additionally, if therepeating unit (1) content is not more than 80 mol %, then the meltviscosity can be made lower. For this reason, the temperature necessaryfor molding the liquid crystal polyester resin easily becomes lower.

The repeating unit (2) content in the liquid crystal polyester resin,relative to the total amount of all repeating units constituting theliquid crystal polyester resin, is preferably at most 35 mol %, morepreferably at least 10 mol % and at most 35 mol %, even more preferablyat least 15 mol % and at most 35 mol %, and particularly preferably atleast 17.5 mol % and at most 32.5 mol %.

The repeating unit (3) content in the liquid crystal polyester resin,relative to the total amount of all repeating units constituting theliquid crystal polyester resin, is preferably at most 35 mol %, morepreferably at least 10 mol % and at most 35 mol %, even more preferablyat least 15 mol % and at most 35 mol %, and particularly preferably atleast 17.5 mol % and at most 32.5 mol %.

In one aspect, the total amount of the repeating units (1), (2) and (3)in the liquid crystal polyester resin does not exceed 100 mol %.

In the liquid crystal polyester resin, the ratio between the repeatingunit (2) content and the repeating unit (3) content, represented by[repeating unit (2) content]/[repeating unit (3) content] (mol %/mol %)(sometimes referred to as molar ratio (2)/(3)), is preferably at least0.9 and at most 1.1, more preferably at least 0.95 and at most 1.05, andeven more preferably at least 0.98 and at most 1.02.

In the liquid crystal polyester resin, the ratio between the repeatingunit (3) content and the repeating unit (1) content, represented by[repeating unit (3) content]/[repeating unit (1) content] (mol %/mol %)(sometimes referred to as molar ratio (3)/(1)), is preferably at least0.2 and at most 1.0, more preferably at least 0.25 and at most 0.85, andeven more preferably at least 0.3 and at most 0.75.

In the liquid crystal polyester resin, the molar ratio y/x in therepeating units (2) should preferably be greater than zero and at most1, more preferably at least 0.1 and at most 0.9, and even morepreferably at least 0.2 and at most 0.8.

x represents the molar content of repeating units in which Ar² is a1,4-phenylene group.

y represents the molar content of repeating units in which Ar² is a1,3-phenylene group.

The aforementioned liquid crystal polyester resin may have just onetype, or may have two or more types of the repeating units (1) to (3),independently of each other. Additionally, the liquid crystal polyesterresin may have one type, or two or more types of repeating units otherthan the repeating units (1) to (3), but the content thereof ispreferably at least 0 mol % and at most 10 mol %, more preferably atleast 0 mol % and at most 5 mol %, relative to the total amount of allrepeating units.

Liquid Crystal Polyester Resin Mixture

In the present embodiment, it is also possible to use a liquid crystalpolyester resin mixture in which multiple types of liquid crystalpolyester resins are mixed. As a result thereof, the melt flowability ofthe liquid crystal polyester resin composition of the present embodimentcan be made better and warping of the resulting molded body can be wellsuppressed.

In this case, it is assumed that the liquid crystal polyester resinmixture is a mixture of liquid crystal polyester resins having mutuallydifferent flow starting temperatures. In the liquid crystal polyesterresin mixture, the liquid crystal polyester resin having the higher flowstarting temperature will be referred to as the first liquid crystalpolyester resin and that having the lower flow starting temperature willbe referred to as the second liquid crystal polyester resin.

In one aspect, the liquid crystal polyester resin according to thepresent embodiment may be a liquid crystal polyester resin mixture.

In another aspect, the liquid crystal polyester resin according to thepresent embodiment may contain a first liquid crystal polyester resinand a second liquid crystal polyester resin, such that the flow startingtemperature of the first liquid crystal polyester resin is higher thanthe flow starting temperature of the second liquid crystal polyesterresin.

The flow starting temperature of the above-mentioned first liquidcrystal polyester resin is preferably at least 300° C., more preferablyat least 310° C., and even more preferably at least 315° C.Additionally, the flow starting temperature of the above-mentioned firstliquid crystal polyester resin is preferably at most 400° C., morepreferably at most 360° C. and even more preferably at most 345° C. Theabove-mentioned upper limit values and lower limit values may bearbitrarily combined.

In one aspect, the flow starting temperature of the above-mentionedfirst liquid crystal polyester resin is preferably at least 300° C. andat most 400° C., more preferably at least 310° C. and at most 360° C.,and even more preferably at least 315° C. and at most 345° C.

If the flow starting temperature of the above-mentioned first liquidcrystal polyester resin is within the above-mentioned range, then ittends to be possible to achieve both melt flowability in the resin andheat resistance in the molded body that is obtained.

On the other hand, the flow starting temperature of the above-mentionedsecond liquid crystal polyester resin is preferably at least 260° C.,more preferably at least 270° C., and even more preferably at least 285°C. Additionally, the flow starting temperature of the above-mentionedsecond liquid crystal polyester resin is preferably at most 350° C.,more preferably at most 320° C., and even more preferably at most 315°C. The above-mentioned upper limit values and lower limit values may bearbitrarily combined.

In one aspect, the flow starting temperature of the above-mentionedsecond liquid crystal polyester resin is preferably at least 260° C. andat most 350° C., more preferably at least 270° C. and at most 315° C.,and even more preferably at least 285° C. and at most 315° C.

If the flow starting temperature of the above-mentioned second liquidcrystal polyester resin is within the above-mentioned range, then itbecomes easier to obtain good flowability in thin portions of molds(i.e., thin-area flowability) and the load deflection temperature of themolded body that is obtained tends to be sufficiently high.

Additionally, in the liquid crystal polyester resin mixture, the amountof the above-mentioned second liquid crystal polyester resin that iscontained, relative to 100 parts by mass of the above-mentioned firstliquid crystal polyester resin, is preferably 100 to 150 parts by mass,more preferably 30 to 120 parts by mass, and even more preferably 50 to100 parts by mass.

The above-mentioned second liquid crystal polyester resin contentrelative to the above-mentioned first liquid crystal polyester resin maybe appropriately set so that a desired state of balance is reachedbetween the load deflection temperature and the thin-area flowability ofthe liquid crystal polyester resin mixture.

The liquid crystal polyester resin mixture may contain a liquid crystalpolyester resin other than the first liquid crystal polyester resin andthe second liquid crystal polyester resin. In that case, in the resinmixture, the resin having the highest flow starting temperature shouldbe defined as the first liquid crystal polyester resin and the resinhaving the lowest flow starting temperature should be defined as thesecond liquid crystal polyester resin.

A liquid crystal polyester resin mixture in which the total amount ofthe first liquid crystal polyester resin and the second liquid crystalpolyester resin relative to the total mass of the liquid crystalpolyester resin mixture is at least 80% by mass and at most 100% by massis preferable.

In the liquid crystal polyester resin mixture, α/β is preferably withinthe range from at least 0.1 to at most 0.6, more preferably within therange from at least 0.3 to at most 0.6.

α represents the molar ratio y/x in the first liquid crystal polyesterresin.

β represents the molar ratio y′/x′ in the second liquid crystalpolyester resin.

x represents the molar content of the repeating units, in the firstliquid crystal polyester resin, in which Ar² is a 1,4-phenylene group.

y represents the molar content of the repeating units, in the firstliquid crystal polyester resin, in which Ar² is a 1,3-phenylene group.

x′ represents the molar content of the repeating units, in the secondliquid crystal polyester resin, in which Ar² is a 1,4-phenylene group.

y′ represents the molar content of the repeating units, in the secondliquid crystal polyester resin, in which Ar² is a 1,3-phenylene group.

Method for Producing Liquid Crystal Polyester Resin

Next, an example of the method for producing the liquid crystalpolyester resin according to the present embodiment will be explained.

The liquid crystal polyester resin of the present embodiment ispreferably produced by means of the acylation step and thepolymerization step indicated below.

The acylation step is a step for obtaining an acylate by acylating aphenolic hydroxy group in a raw material monomer by means of a fattyacid anhydride (for example, acetic anhydride or the like).

In the polymerization step, a liquid crystal polyester resin may beobtained by polymerizing acyl groups in the acylate obtained by theacylation step with carboxy groups in acylates of an aromaticdicarboxylic acid and an aromatic hydroxycarboxylic acid so as to inducetransesterification.

The acylation step and the polymerization step may be performed in thepresence of a heterocyclic organic base compound (sometimes referred toas an imidazole derivative) as represented below.

In the above-mentioned formula (5), R₁ to R₄, each independently,represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, ahydroxymethyl group, a cyano group, a cyanoalkyl group in which thealkyl group has 1 to 4 carbon atoms, a cyanoalkoxy group in which thealkoxy group has 1 to 4 carbon atoms, a carboxy group, an amino group,an aminoalkyl group having 1 to 4 carbon atoms, an aminoalkoxy grouphaving 1 to 4 carbon atoms, a phenyl group, a benzyl group, aphenylpropyl group or a formyl group.

The heterocyclic organic base compound in the above formula (5) ispreferably an imidazole derivative in which RI is an alkyl group having1 to 4 carbon atoms, and R₂ to R₄ are respectively hydrogen atoms.

As a result thereof, the reactivity of the acylation reaction during theacylation step and the transesterification reaction during thepolymerization step can be raised. Additionally, the color of the moldedbody obtained by using the liquid crystal polyester resin composition ofthe present embodiment can be made better.

Among heterocyclic organic base compounds, one or both of 1-methylimidazole and 1-ethyl imidazole are particularly preferred for beingeasily available.

Additionally, the amount of the heterocyclic organic base compound thatis used, when the total amount of the raw material monomers (i.e.,aromatic dicarboxylic acids, aromatic diols and aromatichydroxycarboxylic acids) in the liquid crystal polyester resin isdefined as 100 parts by mass, should preferably be 0.005 to 1 part bymass. Additionally, for the purposes of the color and productivity ofthe molded bodies, it is more preferable for the amount to be 0.05 to0.5 parts by mass relative to 100 parts by mass of the raw materialmonomers.

The heterocyclic organic base compound only needs to exist temporarilyduring the acylation reaction and the transesterification reaction, andthe time of addition thereof may be immediately before the acylationreaction starts, during the acylation reaction, or between the acylationreaction and the transesterification reaction. The liquid crystalpolyester resin obtained in this way has extremely high melt flowabilityand excellent thermal stability.

The amount of the fatty acid anhydride (for example, acetic anhydride orthe like) that is used should be decided by considering the amount ofthe aromatic diols and aromatic hydroxycarboxylic acids, which are theraw material monomers, that are used. Specifically, the amount of thefatty acid anhydride that is used, relative to the total amount of thephenolic hydroxy groups contained in the raw material monomers, ispreferably at least 1.0 times and at most 1.2 times the equivalentamount, more preferably at least 1.0 times and at most 1.15 times theequivalent amount, even more preferably at least 1.03 times and at most1.12 times the equivalent amount, and particularly preferably at least1.05 times and at most 1.1 times the equivalent amount.

If the amount of the fatty acid anhydride that is used relative to thetotal amount of the phenolic hydroxy groups contained in the rawmaterial monomer is at least 1.0 times the equivalent amount, then theacylation reaction progresses easily, unreacted raw material monomers donot tend to remain in the later polymerization step, and as a result,the polymerization proceeds efficiently. Additionally, when theacylation reaction proceeds sufficiently in this way, the raw materialmonomer that has not been acylated is sublimated, and there is less of apossibility that a fractionator that is used at the time ofpolymerization will be blocked. However, if the amount of the fatty acidanhydride that is used is not more than 1.2 times the equivalent amount,then the liquid crystal polyester resin that is obtained cannot beeasily colored.

The acylation reaction in the above-mentioned acylation step ispreferably performed for 30 minutes to 20 hours at a temperature rangefrom 130° C. to 180° C., more preferably for 1 to 5 hours at atemperature from 140° C. to 160° C.

The aromatic dicarboxylic acids used in the above-mentionedpolymerization step may be made to be present in the reaction systemduring the acylation step. In other words, during the acylation step,the aromatic diols, the aromatic hydroxycarboxylic acids and thearomatic dicarboxylic acids may be made to be present in the samereaction system. This is because the carboxy groups and optionallysubstitutable substituent groups in the aromatic dicarboxylic acids areall unaffected by fatty acid anhydrides.

Therefore, it is possible to use a method in which the acylation stepand the polymerization step are sequentially performed after loading anaromatic diol, an aromatic hydroxycarboxylic acid and an aromaticdicarboxylic acid into a reactor, or it is possible to use a method inwhich an aromatic diol and an aromatic dicarboxylic acid are loaded intoa reactor and the acylation step is performed, and thereafter, thearomatic dicarboxylic acid is further loaded into the reactor and thepolymerization step is performed. For the purpose of making theproduction step more convenient, the former method is preferable.

The transesterification reaction in the above-mentioned polymerizationstep is preferably performed while raising the temperature from 130° C.to 400° C. at a temperature increase rate of 0.1 to 50° C./min, and morepreferably performed while raising the temperature from 150° C. to 350°C. at a temperature increase rate of 0.3 to 5° C./min.

Additionally, when performing the transesterification reaction in thepolymerization step, it is preferable to evaporate and distill, out ofthe system, fatty acids (for example, acetic acid and the like) that aregenerated as byproducts and unreacted fatty acid anhydrides (forexample, acetic anhydride and the like), in order to shift theequilibrium. At this time, by refluxing some of the distilled fattyacids back to the reactor, it is possible to condense or desublimate andreturn, to the reactor, raw material monomers and the like that havebeen evaporated or sublimated together with the fatty acids.

In the acylation reaction during the acylation step and thetransesterification reaction during the polymerization step, it ispossible to use a batch device or a continuous device as the reactor. Nomatter which type of reaction device is used, it is possible to obtain aliquid crystal polyester resin that can be used in the presentembodiment.

After the above-mentioned polymerization step, a step for increasing themolecular weight of the liquid crystal polyester resin obtained by thispolymerization step may be performed. For example, it is possible toincrease the molecular weight of the liquid crystal polyester resin bycooling and thereafter grinding the liquid crystal polyester resinobtained in the polymerization step to obtain a powdered liquid crystalpolyester resin, then further heating these powders.

Additionally, the molecular weight of the liquid crystal polyester resinmay be increased by pelletizing the powdered liquid crystal polyesterresin obtained by cooling and grinding, thereby producing a pelletizedliquid crystal polyester resin, and thereafter heating this pelletizedliquid crystal polyester resin. The molecular weight increase usingthese methods is known as solid-phase polymerization in theaforementioned technical field.

Solid-phase polymerization is particularly effective as a method forincreasing the molecular weight of the liquid crystal polyester resin.

By increasing the molecular weight of the liquid crystal polyesterresin, it becomes easy to obtain a liquid crystal polyester resin havinga favorable flow starting temperature, as mentioned below.

As the reaction conditions for the solid-phase polymerization, a methodof heat-treating a resin in the solid state for 1 to 20 hours in aninert gas atmosphere or under reduced pressure is usually employed. Thepolymerization conditions associated with this solid-phasepolymerization can be appropriately optimized after determining the flowstarting temperature of the resin obtained by melt polymerization.Examples of devices used for the heat treatment include known dryers,reactors, inert ovens and electric furnaces.

The flow starting temperature of the liquid crystal polyester resin ispreferably at least 270° C., more preferably 270 to 400° C., and evenmore preferably 280 to 380° C. By using a liquid crystal polyester resinhaving a flow starting temperature in this range, the heat resistance ofa molded body obtained by using the liquid crystal polyester resincomposition in the present embodiment can be made better. Additionally,the thermal stability of the liquid crystal polyester resin can beimproved and thermal degradation can be avoided during the melting andmolding when obtaining the molded body from the liquid crystal polyesterresin composition.

The flow starting temperature, also known as the flow temperature or thefluidity temperature, is the temperature at which, using a capillaryrheometer, a viscosity of 4,800 Pa·s (48,000 poise) is exhibited whenthe liquid crystal polyester is melted and extruded from a nozzle havingan inner diameter of 1 mm and a length of 10 mm, while raising thetemperature at a rate of 4° C./min with a load of 9.8 MPa. The flowstarting temperature serves as an indicator of the molecular weight ofthe liquid crystal polyester (see “Liquid Crystal Polymers—Synthesis,Molding, and Applications—” edited by Naoyuki Koide, pp. 95-105, CMCPublishing Co., Ltd., published Jun. 5, 1987).

A liquid crystal polyester resin having the above-mentioned favorableflow starting temperature can be easily obtained by appropriatelyoptimizing the repeating units constituting the liquid crystal polyesterresin. In other words, when the linearity of molecular chains in theliquid crystal polyester resin is raised, the flow starting temperaturethereof tends to become higher.

For example, repeating units derived from terephthalic acid increase thelinearity of liquid crystal polyester resin molecular chains. On theother hand, repeating units derived from isophthalic acid increase thecurvature (lower the linearity) of liquid crystal polyester resinmolecular chains. For this reason, it is possible to obtain a liquidcrystal polyester resin having a desired flow starting temperature bycontrolling the copolymerization ratio between terephthalic acid andisophthalic acid.

When using the above-mentioned liquid crystal polyester resin mixture,it is preferable for at least one type of liquid crystal polyester resinto be a polymer obtained by polymerizing raw material monomerscontaining an aromatic hydroxycarboxylic acid in the presence of animidazole compound. Liquid crystal polyester resins obtained in this wayhave extremely high flowability when melted and also have excellentthermal stability.

Additionally, in the liquid crystal polyester resin according to thepresent embodiment, it is preferable to optimize the copolymerizationratio between terephthalic acid and isophthalic acid. In this way, it ispossible to control the linearity of the molecular chains in the liquidcrystal polyester resin as mentioned above. As a result thereof, it ispossible to produce each of multiple types of liquid crystal polyesterresins having flow starting temperatures that are different from eachother.

Glass Component

The glass components included in the liquid crystal polyester resincomposition of the present embodiment contain glass fibers having alength of more than 50 μm and glass fine powders (hereinafter sometimesreferred to simply as “fine powders”) having a length of at least 4 μmand at most 50 μm.

In one aspect, the glass components may further contain glass ultrafinepowders (hereinafter sometimes referred to simply as “ultrafinepowders”) having a length of less than 4 μm.

The length of the glass components included in the liquid crystalpolyester resin composition of the present embodiment is the major axisof circumscribed rectangle of the glass components in binarized scanningelectron microscope (SEM) images. The major axis of circumscribedrectangle refers to the length of a long side when a glass componentparticle is surrounded by a circumscribed rectangle. The method foranalyzing the glass components using a SEM will be explained below.

In one aspect, the glass fibers are glass component particles for whichthe major axis of circumscribed rectangle in the above-mentioned SEMimages is more than 50 μm, fine powders are glass component particlesfor which the major axis of circumscribed rectangle in theabove-mentioned SEM images is at least 4 μm and at most 50 μm, andultrafine powders are glass component particles for which the major axisof circumscribed rectangle in the above-mentioned SEM images is lessthan 4 μm.

Glass Fiber

The number-average fiber length of the glass fibers contained in theliquid crystal polyester resin composition of the present embodiment isat last 200 μm and at most 400 μm.

If the number-average fiber length of the glass fibers is at least 200μm, then the mechanical strength of molded bodies using virgin materialcan be made sufficiently higher. Additionally, if the number-averagefiber length of the glass fibers in the present embodiment is not morethan 400 μm, then the glass fibers tend not to be physically destroyedwhen reground. As a result thereof, mechanical strength decreases causedby the physical destruction of the glass fibers can be suppressed.Therefore, the mechanical strength retention rate when reground can bemade sufficiently high.

The number-average fiber length of the above-mentioned glass fibers ispreferably at least 210 μm, more preferably at least 220 μm, and evenmore preferably at least 230 μm. Additionally, the number-average fiberlength of the above-mentioned glass fibers is preferably at most 380 μm,and more preferably at most 350 μm.

In one aspect, the number-average fiber length of the above-mentionedglass fibers is preferably at least 210 μm and at most 380 μm, morepreferably at least 220 μm and at most 350 μm, even more preferably atleast 230 μm and at most 350 μm, and may be at least 234 μm and at most314 μm.

The glass fibers contained in the liquid crystal polyester resincomposition in the present embodiment preferably have a substantiallycircular cross-sectional shape in the radial direction. It is possibleto confirm, by SEM, whether the above-mentioned glass fibers have asubstantially circular cross-sectional shape in the radial direction.The diameter of the above-mentioned glass fibers is preferably at least5 μm and at most 17 μm, more preferably at least 6 μm and at most 15 μm,and even more preferably at least 9 μm and at most 12 μm.

The diameter of the glass fibers can be determined by means of a glassfiber diameter measurement method to be explained below.

Fine Powder

The fine powder contained in the liquid crystal polyester resincomposition in the present embodiment preferably has a substantiallycircular cross-sectional shape in the radial direction. In the presentdescription, the radial direction of the fine powders is the directionof the minor axis of circumscribed rectangle of fine powder particles inbinarized SEM images. The minor axis of circumscribed rectangle refersto the length of a short side when a particle is surrounded by acircumscribed rectangle. It is possible to confirm, by SEM, whether theabove-mentioned fine powders have a substantially circularcross-sectional shape in the radial direction. The diameter of theabove-mentioned fine power is preferably at least 5 μm and at most 17μm, more preferably at least 6 μm and at most 15 μm, and even morepreferably at least 9 μm and at most 12 μm.

The diameter of the above-mentioned fine powders can be determined bymeans of the measurement method described in <Measurement 2 of GlassComponents in Liquid Crystal Polyester Resin Composition> below.

The aspect ratio (length/diameter) of the fine powders contained in theliquid crystal polyester resin composition of the present embodiment ispreferably at least 0.3 and more preferably at least 0.5. Additionally,the aspect ratio of the fine powders is preferably at most 5.6 and morepreferably at most 5.3.

In one aspect, the aspect ratio (length/diameter) of the fine powderscontained in the liquid crystal polyester resin composition of thepresent embodiment is preferably at least 0.3 and at most 5.6.

The fine powders contained in the liquid crystal polyester resincomposition of the present embodiment are composed of first fine powdershaving a length of at least 4 μm and at most 40 μm (hereinaftersometimes referred to simply as “first fine powders”), and second finepowders having a length of more than 40 μm and at most 50 μm(hereinafter sometimes referred to simply as “second fine powders”).

In one aspect, the fine powders according to the present embodiment arecomposed of first fine powders that are glass components having a majoraxis of circumscribed rectangle of at least 4 μm and at most 40 μm inthe above-mentioned SEM images, and second fine powders that is glasscomponents having a major axis of circumscribed rectangle of more than40 μm and at most 50 μm in the above-mentioned SEM images.

Content Ratio

The liquid crystal polyester resin composition in the present embodimentcontains at least 5 parts by mass and at most 100 parts by mass of theglass components relative to 100 parts by mass of the liquid crystalpolyester. If the glass component content is at least 5 parts by massand at most 100 parts by mass, it is possible to obtain both moldabilityof the liquid crystal polyester resin composition and mechanicalstrength in the molded body.

The liquid crystal polyester resin composition preferably contains atleast 10 parts by mass and at most 70 parts by mass, and more preferablyat least 20 parts by mass and at most 60 parts by mass of the glasscomponents relative to 100 parts by mass of the liquid crystalpolyester.

In another aspect, the liquid crystal polyester resin composition maycontain at least 29 parts by mass and at most 43 parts by mass of theglass components relative to 100 parts by mass of the liquid crystalpolyester.

In one aspect, the glass component content in the liquid crystalpolyester resin composition of the present embodiment is preferably 5 to30% by mass relative to the total mass of the liquid crystal polyesterresin composition.

The liquid crystal polyester resin content in the liquid crystalpolyester resin composition of the present embodiment is preferably 60to 90% by mass relative to the total mass of the liquid crystalpolyester resin composition.

The liquid crystal polyester resin composition of the present embodimentcontains at least 20% and at most 95% of the fine powders relative tothe total number of the glass components.

If the content of the fine powders relative to the total number of theglass components in the liquid crystal polyester resin composition ofthe present embodiment is at least 20%, then the influence of thephysical destruction of the glass components when reground can bereduced. Therefore, the mechanical strength retention rate when regroundcan be made sufficiently high.

In the liquid crystal polyester resin composition of the presentembodiment, the content of the fine powders relative to the total numberof the glass components is preferably at least 50% and more preferablyat least 70%.

Additionally, in the liquid crystal polyester resin composition of thepresent embodiment, if the content of the fine powders relative to thetotal number of the glass components is not more than 95%, then themechanical strength of molded bodies composed of virgin material can bemade sufficiently high.

In the liquid crystal polyester resin composition of the presentembodiment, the content of the fine powders relative to the total numberof the glass components is preferably at most 90%.

In one aspect, the content of the fine powders relative to the totalnumber of the glass components is preferably at least 50% and at most90%, and particularly preferably at least 70% and at most 90%.

In another aspect, the content of the fine powders relative to the totalnumber of the glass components is preferably at least 73% and at most88%

The liquid crystal polyester resin composition of the present embodimentpreferably contains at least 40% and less than 90% of the first finepowders relative to the total number of the glass components.

In another aspect, the content of the first fine powders may be at least69% and at most 85% relative to the total number of the glasscomponents.

If the content of the first fine powders relative to the total number ofthe glass components is at least 40%, then the influence of the physicaldestruction of the glass components when reground can be reduced.Therefore, the mechanical strength retention rate when reground can bemade sufficiently high.

Additionally, if the content of the first fine powders relative to thetotal number of the glass components is less than 90%, then themechanical strength of molded bodies composed of virgin material can bemade sufficiently high.

Therefore, if the content of the first fine powders relative to thetotal number of the glass components is at least 40% and less than 90%,then the mechanical strength retention rate when reground can be madehigher.

In the liquid crystal polyester resin composition of the presentembodiment, the upper limit value and the lower limit value of thecontent of the first fine powders may be combined, within the possiblerange, with the upper limit value and the lower limit value of thecontent of the fine powders.

In one aspect, the content of the first fine powders in theabove-mentioned glass components does not exceed the content of theabove-mentioned fine powders in the glass components.

In one aspect, the content of the second fine powders in the liquidcrystal polyester resin composition of the present embodiment ispreferably at least 40% and less than 90% relative to the total numberof the glass components.

Glass Component Analysis Method

The method for measuring the length of the glass components will beexplained. First, 5 g of pellets comprising the liquid crystal polyesterresin composition of the present embodiment are heated in a mufflefurnace (manufactured by Yamato Scientific Co., Ltd., “FP410”) at 600°C. for 4 hours in an air atmosphere, thereby removing the resin andobtaining incinerated residues containing the glass components. Anamount of the incinerated sample, weighing 0.3 g, is loaded into 50 mLof purified water, and a 0.5 vol % aqueous solution of micro-90(manufactured by Sigma-Aldrich Japan) is added as a surfactant in orderto improve the dispersion properties, thereby obtaining a mixedsolution. The mixed solution that is obtained is subjected to ultrasonicwaves for 5 minutes to uniformly disperse the incinerated sample in thepurified water, thereby obtaining a sample solution.

Next, this sample solution in which the glass components are dispersedin purified water is transferred to a 5 mL sample cup by means of apipette and diluted 5 times with purified water, thereby obtaining asample solution. Using a particle shape image analysis device (“PITA3”manufactured by Seishin Enterprise Co., Ltd.) under the conditionsindicated below, the obtained sample solution is passed through a flowcell and images of the glass component particles moving through thefluid are captured one at a time. In the above-mentioned measurementmethod, the time at which the number of glass component particlesaccumulated from the measurement starting time reaches 5000 is definedas the measurement ending time.

Conditions

Number of measurements: 5000

Dispersion solvent: water

Dispersion conditions: 0.5 vol % aqueous solution of micro-90 as carriersolution 1 and carrier solution 2

Sample solution speed: 2.08 μL/s

Carrier solution 1 speed: 333.33 μL/s

Carrier solution 2 speed: 333.33 μL/s

Observation magnification: objective, 10×

The obtained images are binarized, the major axis of circumscribedrectangle of the glass component particles are measured in the processedimages and defined as the lengths of the glass component particles.

As the number-average fiber length of the glass fibers in the presentembodiment, the average value of the measured values (major axis ofcircumscribed rectangle) is employed for the glass fibers having alength greater than 50 μm in the above-mentioned processed images.

The content of the fine powders relative to the total number of theglass components in the present embodiment can be calculated by dividingthe number of particles of the fine powders having a length of at least4 μm and at most 50 μm by the total number (for example, 5000) of theglass component particles in the above-mentioned processed images.

The content of the first fine powders relative to the total number ofthe glass components in the present embodiment can be calculated bydividing the number of particles of the first fine powders having alength of at least 4 μm and at most 40 μm by the total number (forexample, 5000) of the glass component particles in the above-mentionedprocessed images.

The content of the second fine powders relative to the total number ofthe glass components in the present embodiment can be calculated bydividing the number of particles of the second fine powders having alength (major axis of circumscribed rectangle) of more than 40 μm and atmost 50 μm by the total number (for example, 5000) of the glasscomponent particles in the above-mentioned processed images.

The method for measuring the diameter of the glass fibers in the presentembodiment will be explained. As the diameter of the glass fibers in thepresent embodiment, incinerated residues containing the above-mentionedglass components are observed by a SEM at 1000-times magnification, thediameters (i.e., the minor axis of circumscribed rectangle) of 100 glassfibers randomly selected from the SEM images are respectively measured,and the average value of the 100 measured values is employed.

The method for measuring the diameter of the fine powders in the presentembodiment will be explained. First, incinerated residues containing theabove-mentioned glass components are observed by a SEM at 1000-timesmagnification. The obtained images are binarized, and in the processedimages, the radial lengths (i.e., the minor axis of circumscribedrectangle) of 100 particles of the fine powders randomly selected fromthe processed images are measured, and the average value of the 100measured values is taken as the diameter of the fine powders.

The aspect ratio of the fine powders in the present embodiment can becalculated, in the images obtained with the above-mentioned particleshape image analysis device, by defining the directions substantiallyaligned with the diameters of the particles of the fine powders measuredin the above-mentioned method as the radial directions of the finepowder particles, and calculating length/diameter for these fine powderparticles.

Glass Component Preparation Method

The number-average fiber length of the glass fibers contained in theliquid crystal polyester resin composition can be adjusted by adjustingthe melt-kneading conditions when producing the liquid crystal polyesterresin composition. For example, in order to make the number-averagefiber length of the glass fibers contained in the liquid crystalpolyester resin composition smaller, it is effective to use means suchas raising the rotation speed of a screw that is used, lowering thecylinder temperature, increasing the melt viscosity of the melted resin,or increasing the shearing force.

The fine powders contained in the liquid crystal polyester resincomposition of the present embodiment may be produced by grinding acommercially available fibrous glass filler (hereinafter sometimesreferred to as “base fibers”). In the present embodiment, the finepowders may be blended into the liquid crystal polyester resin so thatthe content of the fine powders relative to the total number of theglass components contained in the liquid crystal polyester resincomposition is within the range from at least 20% to at most 95%.Additionally, in the method for producing the liquid crystal polyesterresin composition to be explained below, the content of the fine powdersmay be controlled so as to be within the range from at least 20% to atmost 95% relative to the total number of the glass components byappropriately modifying the production conditions.

The base fibers according to the present embodiment are not particularlylimited, but examples include fillers produced by various methods, suchas long-fiber type chopped glass fibers, short-fiber type milled glassfibers and the like. Among these, the above-mentioned base fibers arepreferably chopped glass fibers. The above-mentioned base fibers may bea single type used alone, or may be a combination of two or more types.

Examples of the types of the above-mentioned base fibers includeE-glass, A-glass, C-glass, D-glass, AR-glass, R-glass, S-glass ormixtures thereof. Among these, E-glass is preferable for havingexcellent strength and being easily available.

As the above-mentioned base fibers, weakly alkaline fibers haveexcellent mechanical strength (tensile strength and Izod impactstrength) and can be favorably used. In particular, glass fibers inwhich the silicon oxide content is at least 50% by mass and at most 80%by mass relative to the total mass of the above-mentioned glass fibersare preferably used, and glass fibers in which the silicon oxide contentis at least 65% by mass and at most 77% by mass are more preferablyused.

The above-mentioned base fibers may be fibers that have been treated, asneeded, with a coupling agent such as a silane-based coupling agent or atitanium-based coupling agent.

The above-mentioned base fibers may be coated with a thermoplastic resinsuch as a urethane resin, an acrylic resin, an ethylene/vinyl acetatecopolymer or the like, or with a heat-curable resin such as an epoxyresin. Additionally, the above-mentioned base fibers may be processedwith a sizing agent.

The number-average fiber length of the base fibers is preferably atleast 20 μm and at most 6000 μm.

If the number-average fiber length of the base fibers is at least 20 μm,then the reinforcement effect of the obtained molded bodies issufficiently high. Additionally, if the number-average fiber length ofthe base fibers is not more than 6000 μm, then the number-average fiberlength of the glass fibers contained in the liquid crystal polyesterresin composition after melt-kneading can be easily adjusted to be notmore than 400 μm.

The number-average fiber length of the base fibers provided formelt-kneading is more preferably at least 1000 μm and even morepreferably at least 2000 μm. The number-average fiber length of the basefibers is more preferably at most 5000 μm, and even more preferably atmost 4500 μm.

In one aspect, the number-average fiber length of the base fibersprovided for melt-kneading is more preferably at least 1000 μm and atmost 5000 μm, and even more preferably at least 2000 μkm and at most4500 μm.

The fiber diameter (also referred to as the single-fiber diameter) ofthe base fibers provided for melt-kneading is preferably at least 5 μmand at most 17 μm. If the fiber diameter of the base fibers is at least5 μm, then the reinforcement effect on the obtained molded bodies issufficiently high. Additionally, if the fiber diameter of the basefibers is not more than 17 μm, then the melt flowability of the liquidcrystal polyester resin composition is sufficiently high.

The fiber diameter of the base fibers provided for melt-kneading is morepreferably at least 6 μm, and even more preferably at least 9 μm.Additionally, the fiber diameter of the base fibers is more preferablyat most 15 μm, and even more preferably at most 12 μm.

In one aspect, the fiber diameter of the base fibers provided formelt-kneading is preferably at least 6 μm and at most 15 μm, and evenmore preferably at least 9 μm and at most 12 μm.

The fiber diameter of the base fibers remains substantially unchangedeven after melt-kneading.

Method for Measuring Number-Average Fiber Length and Fiber Diameter ofBase Fibers

The “number-average fiber length of the base fibers” in the presentdescription, where not particularly noted, refers to a value measured bythe method described in JIS R3420 “7.8 Length of Chopped Strands”.

Additionally, the “fiber diameter of the base fibers” in the presentdescription, where not particularly noted, refers to a value measured by“method A” among the methods described in JIS R3420 “7.6 Single-FiberDiameter”.

Other Components

The liquid crystal polyester resin composition may contain at least onetype of another component such as a filler other than the glasscomponents in the present embodiment, an additive, a resin other thanthe liquid crystal polyester resin or the like, within a range such thatthe effects of the present invention are obtained.

In one aspect, the amount of the other components contained in theliquid crystal polyester resin composition in the present embodiment ispreferably 5 to 40% by mass relative to the total mass of the liquidcrystal polyester resin composition.

The filler other than the glass components in the embodiment may be afibrous filler or may be a flake-shaped filler, and other than fibrousand flake-shaped, may be a spherical or other particulate filler.Additionally, the filler may be an inorganic filler or may be an organicfiller.

Examples of fibrous fillers that are inorganic fillers include carbonfibers such as PAN-based carbon fibers and pitch-based carbon fibers;ceramic fibers such as silica fibers, alumina fibers and silica-aluminafibers; and metallic fibers such as stainless steel fibers. Additionalexamples include whiskers such as potassium titanate whiskers, bariumtitanate whiskers, wollastonite whiskers, aluminum borate whiskers,silicon nitride whiskers and silicon carbide whiskers.

Examples of fibrous fillers that are organic fillers include polyesterfibers, aramid fibers and cellulose fibers.

Examples of flake-shaped fillers that are inorganic fillers includetalc, mica, graphite, wollastonite, glass flakes, barium sulfate andcalcium carbonate. Mica may be muscovite, phlogopite, fluorophlogopiteor tetrasilicic mica.

Examples of particulate fillers that are inorganic fillers includesilica, alumina, titanium oxide, glass beads, glass balloons, boronnitride, silicon carbide and calcium carbonate.

Examples of additives include additives that are usually used in resincompositions. Examples of such additives include stabilizers, UVabsorbers, plasticizers, flame retardants, flame retardant promoters,anti-static agents, surfactants, colorants, lubricants, mold releaseagents and the like.

Examples of stabilizers include hindered phenols, hydroquinone,phosphites, substitutions thereof and the like.

Examples of UV absorbers include resorcinol, salicylate, benzotriazole,benzophenone and the like.

Examples of colorants include materials containing dyes such asnitrosine, and pigments such as cadmium sulfide, phthalocyanine, carbonblack and the like.

Examples of lubricants include stearic acid, montanic acid, estersthereof, half-esters thereof with polyhydric alcohols, stearyl alcohol,stearamide, polyethylene waxes and the like.

The moldability of the liquid crystal polyester resin composition of thepresent embodiment can be improved by further adding a mold releaseagent. Examples of the mold release agent include montanic acid, saltsthereof, esters thereof, half-esters thereof with polyhydric alcohols,stearyl alcohol, stearamide, polyethylene waxes and the like, andpreferably, fatty acid esters of pentaerythritol.

The blended amount of the mold release agent is preferably at least 0.1parts by mass and at most 0.5 parts by mass, more preferably at least0.2 parts by mass and at most 0.4 parts by mass, relative to 100 partsby mass of the liquid crystal polyester resin. If the blended amount ofthe mold release agent is at least 0.1 parts by mass and at most 0.5parts by mass, then there is a tendency for contamination of the moldbeing used, swelling of the molded body or the like to be less likely tooccur, and mold release effects are more easily obtained.

Examples of resins other than the liquid crystal polyester includethermoplastic resins other than liquid crystal polyester, such aspolypropylenes, polyamides, polyesters other than liquid crystalpolyesters, polysulfones, polyethersulfones, polyphenylene sulfides,polyetherketones, polycarbonates, polyphenylene ethers andpolyetherimides; and heat-curable resins such as phenol resins, epoxyresins, polyimide resins, cyanate resins and the like. The amount ofresins other than liquid crystal polyester that is contained is usually0 to 20 parts by mass relative to 100 parts by mass of the liquidcrystal polyester.

Method for Producing Liquid Crystal Polyester Resin Composition

The liquid crystal polyester resin composition is preferably prepared bymelt-kneading the liquid crystal polyester resin, the glass componentsand optionally other components, by means of an extruder, and extrudingthe mixture in pellet form.

The glass components that are used may be prepared in advance so thatthe content of the fine powders will be within the range from at least20% to at most 95% relative to the total number of the glass components.Additionally, it is possible to use a commercially available fibrousglass filler as a raw material, and to implement control so that thisfibrous filler is broken during the production of the liquid crystalpolyester resin composition, thereby causing the content of the finepowders relative to the total number of the glass components containedin the liquid crystal polyester resin composition to be within the rangefrom at least 20% to at most 95%.

The extruder preferably has a cylinder, at least one screw provided inthe cylinder, and at least one supply port provided in the cylinder.Furthermore, it is more preferable for at least one vent portion to beprovided in the cylinder.

Furthermore, in the present embodiment, an extremely large amount ofenergy is required to break the fine powders having a length of at least4 μm and at most 50 μm. Thus, it is known that the fine powders are lesslikely to undergo physical destruction than glass fibers are. Therefore,in a reground material to which the liquid crystal polyester resincomposition of the present embodiment is applied, it can be expectedthat the fine powders will not change even when melted inside a screwduring injection molding.

According to the liquid crystal polyester resin composition having aconfiguration as indicated above, a liquid crystal polyester resincomposition having a high mechanical strength retention rate whenreground is obtained.

Molded Body

The molded body in the present embodiment has the above-mentioned liquidcrystal polyester resin composition as the forming material.

As the molding method of the liquid crystal polyester resin compositionof the present embodiment, a melt molding method is preferred. Examplesthereof include injection molding methods; extrusion molding methodssuch as T-die methods and inflation methods; compression moldingmethods; blow molding methods; vacuum molding methods; and press moldingmethods. Among these, injection molding methods are preferred.

Examples of products and components that are molded bodies formed fromthe liquid crystal polyester resin composition include: bobbins such asoptical pickup bobbins and transformer bobbins; relay components such asrelay cases, relay bases, relay sprues and relay armatures; connectorssuch as RTMM connectors, DDR connectors, CPU sockets, S/O connectors,DIMM connectors, board-to-board connectors, FPC connectors and cardconnectors; reflectors such as lamp reflectors and LED reflectors;holders such as lamp holders and heater holders; diaphragms such asspeaker diaphragms; separation claws such as separation claws forcopiers and separation claws for printers; camera module components;switch components; motor components; sensor components; hard disk drivecomponents; tableware such as ovenware; vehicle components; aircraftcomponents; and sealing members such as semiconductor element sealingmembers and coil sealing members.

Additionally, examples other than the above include copyingmachine/printer-related components such as separation claws and heaterholders; mechanical components such as impellers, fan gears, gears,bearings, motor components and cases; automotive/vehicle-relatedcomponents such as automotive machinery components, variousfuel-related, exhaust and intake pipes, various exhaust-gas, coolant andoil temperature sensors, air conditioner thermostat bases, airconditioner motor insulators, radiator motor brush holders, wipermotor-related components, distributors, starter switches, starterrelays, transmission wire harnesses, air conditioner panel switchsubstrates, fuel-related solenoid valve coils, fuse connectors, ECUconnectors, horn terminals, electrical component insulation plates, lampsockets, lamp reflectors, lamp housings, brake pistons, solenoidbobbins, engine oil filters and ignition device cases; cooking equipmentsuch as microwave cooking pans and heat-resistant tableware;construction materials or civil engineering materials including thermalinsulation or soundproofing materials such as flooring materials andwall materials, support materials such as beams and columns, and roofingmaterials; aircraft, spacecraft and space instrument components;radiation installation elements for nuclear reactors and the like;marine installation elements; cleaning instruments; optical instrumentcomponents; valves; pipes; nozzles; filters; membranes; medicalinstrument components and medical materials; sensor components; sanitarysupplies; sports equipment; leisure equipment and the like.

Molded Body Mechanical Strength Evaluation Method

The mechanical strength of the molded body is evaluated by measuring thetensile strength and the Izod impact strength.

The tensile strength of the molded body is measured in accordance withthe ASTM D638 standard using an ASTM No. 4 test piece produced by aninjection molder using the liquid crystal polyester resin composition.

The Izod impact strength of the molded body is measured in accordancewith the ASTM D256 standard using a test piece obtained by halving, inthe length direction, a test piece having a length of 127 mm, a width of12.7 mm and a thickness of 6.4 mm, produced by an injection molder usingthe liquid crystal polyester resin composition.

With a molded body having a structure as mentioned above, theabove-mentioned liquid crystal polyester resin composition is used andthus, a molded body having a high mechanical strength retention ratewhen reground is obtained.

In one aspect, the liquid crystal polyester resin composition of thepresent embodiment is a liquid crystal polyester resin that:

comprises a liquid crystal polyester resin, glass components, andoptionally other components;

the liquid crystal polyester resin is a liquid crystal polyestercontaining repeating units derived from 4-hydroxybenzoic acid, repeatingunits derived from 4,4′-dihydroxybiphenyl, repeating units derived fromterephthalic acid, and repeating units derived from isophthalic acid;

the glass components include glass fibers having a length of more than50 μm and glass fine powders having a length of at least 4 μm and atmost 50 μm;

the fine powders are composed of first fine powders having a length ofat least 4 μm and at most 40 μm, and second fine powders having a lengthof more than 40 μm and at most 50 μm;

the number-average fiber length of the glass fibers is at least 200 μmand at most 400 μm, preferably at least 210 μm and at most 380 μm, morepreferably at least 220 μm and at most 350 μm, even more preferably atleast 230 μm and at most 350 μm, and particularly preferably at least234 μm and at most 314 μm;

the diameter of the fine powders is preferably at least 5 μm and at most17 μm, more preferably at least 6 μin and at most 15 μm, and even morepreferably at least 9 μm and at most 12 μm;

the liquid crystal polyester resin content relative to the total amountof the liquid crystal polyester resin composition is 60 to 90% by mass;

the glass component content, relative to 100 parts by mass of the liquidcrystal polyester resin, is at least 5 parts by mass and at most 100parts by mass, preferably at least 10 parts by mass and at most 70 partsby mass, more preferably at least 20 parts by mass and at most 60 partsby mass, and particularly preferably at least 29 parts by mass and atmost 43 parts by mass;

the content of the fine powders, relative to the total number of theglass components, is at least 20% and at most 95%, preferably at least50% and at most 90%, more preferably at least 70% and at most 90%, andmay be at least 73% and at most 88%; and

the content of the first fine powders is at least 40% and less than 90%,and may be at least 69% and at most 85% relative to the total number ofthe glass components.

In another aspect, the liquid crystal polyester resin composition of thepresent embodiment is a liquid crystal polyester resin compositionwherein:

when the Izod impact strength retention rate is determined under theconditions described in the examples below, the Izod impact strengthretention rate is at least 90%; and

when the tensile strength retention rate is determined under theconditions described in the examples below, the tensile strengthretention rate is at least 90%.

EXAMPLES

Hereinafter, examples of the present invention will be explained.However, the present invention is not limited to these examples. Themeasurements were performed as indicated below.

Flow Starting Temperature of Liquid Crystal Polyester Resin

Using a flow tester (“Model CFT-500EX” from Shimadzu Corp.), 2 g ofliquid crystal polyester were loaded into a cylinder equipped with a diehaving a nozzle with an inner diameter of 1 mm and a length of 10 mm,the liquid crystal polyester was melted and extruded from the nozzlewith a load of 9.8 MPa while raising the temperature at a rate of 4°C./min, and the temperature at which a viscosity of 4800 Pa·s (48000poise) was exhibited was measured.

Measurement 1 of Glass Components in Liquid Crystal Polyester ResinComposition

First, 5 g of pellets comprising the liquid crystal polyester resincomposition of the present example were heated in a muffle furnace(manufactured by Yamato Scientific Co., Ltd., “FP410”) at 600° C. for 4hours in an air atmosphere, thereby removing the resin and obtainingincinerated residues containing the glass components. An amount of theincinerated sample, weighing 0.3 g, was loaded into 50 mL of purifiedwater, and a 0.5 vol % aqueous solution of micro-90 (manufactured bySigma-Aldrich Japan) was added as a surfactant in order to improve thedispersion properties, thereby obtaining a mixture. The obtained mixturewas subjected to ultrasonic waves for 5 minutes to uniformly dispersethe incinerated sample in the purified water, thereby obtaining a samplesolution.

Next, this sample solution in which the glass components were dispersedwas transferred to a 5 mL sample cup by means of a pipette and diluted 5times with purified water, thereby obtaining a sample solution. Using aparticle shape image analysis device (“PITA-3” manufactured by SeishinEnterprise Co., Ltd.) under the conditions described below, the obtainedsample solution was passed through a flow cell and images of the glasscomponent particles moving through the fluid were captured one at atime.

Conditions

Number of measurements: 5000

Dispersion solvent: water

Dispersion conditions: 0.5 vol % aqueous solution of micro-90 as carriersolution 1 and carrier solution 2

Sample solution speed: 2.08 μL/s

Carrier solution 1 speed: 333.33 μL/s

Canier solution 2 speed: 333.33 μL/s

Observation magnification: 10× objective

Length of Glass Component

The length of each glass component particle was determined by binarizingthe obtained images and measuring the major axis of circumscribedrectangle of the glass component particles in the processed images.

Content of Fine Powders Relative to Total Number of Glass Components

The amount of the fine powders relative to the total number of the glasscomponents was calculated by dividing the number of particles of thefine powders having a length of at least 4 μm and at most 50 μm by thetotal number (i.e., 5000 in the above example) of glass componentparticles in the above-mentioned processed images.

Content of First Fine Powders Relative to Total Number of GlassComponents

The content of the first fine powders relative to the total number ofthe glass components was calculated by dividing the number of particlesof the first fine powders having a length of at least 4 μm and at most40 μm by the total number (i.e., 5000 in the above example) of glasscomponent particles in the above-mentioned processed images.

Measurement 2 of Glass Components in Liquid Crystal Polyester ResinComposition Diameter of Fine Powder

The incinerated residues obtained in the above-described <Measurement1>were observed at 1000-times magnification using a SEM (“S-4700” fromHitachi, Ltd.). The obtained images were binarized, the radial lengths(i.e., the minor axis of circumscribed rectangle) of 100 fine powderparticles randomly selected from the processed images were measured, andthe average value of the 100 measured values was taken as the finepowder diameter.

Number-Average Fiber Length of Glass Fibers Having Length More than 50μm

The number-average fiber lengths of the glass fibers were calculatedusing the measured value of glass fibers having a length of more than 30μm in the above-mentioned processed images.

(A) Production of Liquid Crystal Polyester Resin Production Example 1(Liquid Crystal Polyester Resin (A-1))

A reactor equipped with a stirring device, a torque meter, a nitrogengas feeding pipe, a thermometer and a reflux cooler was loaded with994.5 g (7.2 moles) of 4-hydroxybenzoic acid, 446.9 g (2.4 moles) of4,4′-dihydroxybiphenyl, 299.0 g (1.8 moles) of terephthalic acid, 99.7 g(0.6 moles) of isophthalic acid and 1347.6 g (13.2 moles) of aceticanhydride, 0.2 g of 1-methylimidazole were added as a catalyst and theatmosphere inside the reactor was well-substituted with nitrogen gas.

Thereafter, while stirring the mixture in a nitrogen gas flow, thetemperature was raised from room temperature to 150° C. over 30 minutesand the mixture was refluxed for 30 minutes while maintaining the sametemperature.

Next, 2.4 g of 1-methylimidazole were added. Thereafter, whiledistilling away acetic acid byproducts and unreacted acetic anhydride,the temperature was raised from 150° C. to 320° C. over 2 hours and 50minutes, and held at 320° C. for 30 minutes. After holding thetemperature, the contents were extracted and cooled to room temperature.

The obtained solids were ground to a particle size of 0.1 to 1 mm in agrinder, after which solid phase polymerization was performed, in anitrogen atmosphere, by raising the temperature from room temperature to250° C. over 1 hour, raising the temperature from 250° C. to 296° C.over 5 hours, and holding the temperature at 296° C. for 3 hours. Afterthe solid phase polymerization, cooling was performed, thereby obtaininga powdered liquid crystal polyester resin (A-1). The flow startingtemperature of the obtained liquid crystal polyester resin (A-1) was328° C.

Production Example 2 (Liquid Crystal Polyester Resin (A-2))

A reactor equipped with a stirring device, a torque meter, a nitrogengas feeding pipe, a thermometer and a reflux cooler was loaded with994.5 g (7.2 moles) of 4-hydroxybenzoic acid, 446.9 g (2.4 moles) of4,4′-dihydroxybiphenyl, 239.2 g (1.44 moles) of terephthalic acid, 159.5g (0.96 moles) of isophthalic acid and 1347.6 g (13.2 moles) of aceticanhydride, 0.2 g of 1-methylimidazole were added as a catalyst and theatmosphere inside the reactor was well-substituted with nitrogen gas.

Thereafter, while stirring the mixture in a nitrogen gas flow, thetemperature was raised from room temperature to 150° C. over 30 minutesand the mixture was refluxed for 1 hour while maintaining the sametemperature.

Next, 0.9 g of 1-methylimidazole were added, and while distilling awayacetic acid byproducts and unreacted acetic anhydride, the temperaturewas raised from 150° C. to 320° C. over 2 hours and 50 minutes, and heldat 320° C. for 30 minutes. After holding the temperature, the contentswere extracted and cooled to room temperature.

The obtained solids were ground to a particle size of 0.1 to 1 mm in agrinder, and solid phase polymerization was performed, in a nitrogenatmosphere, by raising the temperature from room temperature to 220° C.over 1 hour, raising the temperature from 220° C. to 241° C. over 0.5hours, and holding the temperature at 241° C. for 10 hours. After thesolid phase polymerization, cooling was performed, thereby obtaining apowdered liquid crystal polyester resin (A-2). The flow startingtemperature of the obtained liquid crystal polyester resin (A-2) was292° C.

Additionally, in the examples below, the commercially available productsindicated below were used as the glass components. However, thenumber-average fiber lengths indicated below are nominal values from themanufacturers, and the values do not take fine powders into account. Theshapes described for each filler represent the shapes of radial crosssections of the respective fillers.

Filler A: CS3J260S (manufactured by Nitto Boseki Co., Ltd.,substantially circular, diameter 10 μm, number-average fiber length 3mm)

Filler B: PF20E-001 (manufactured by Nitto Boseki Co., Ltd.,substantially circular, diameter 10 μm, number-average fiber length 20μm)

Additionally, the raw material indicated below was used in the examplesbelow. Mold release agent: Loxiol VPG861 (manufactured by EmeryOleochemicals Japan Ltd., mixture of full ester (tetrastearate) andpartial ester of pentaerythritol and stearic acid, 5% mass reductiontemperature 310° C.)

Production of Liquid Crystal Polyester Resin Composition (VirginMaterial) Examples 1 to 4 and Comparative Examples 1 to 3

Glass components were prepared in advance by mixing glass fibers havinga length of more than 50 μm, fine powders and ultrafine powders. Aliquid crystal polyester resin, the glass components and a mold releaseagent were melt-kneaded, at the ratios indicated in Table 1 and Table 2,using a twin-screw extruder (manufactured by Ikegai Corp., “PCM-30HS”)with a cylinder temperature of 340° C., to obtain a pellet-shaped liquidcrystal polyester resin composition. The liquid crystal polyester resincomposition was produced using a water-sealed vacuum pump (manufacturedby Shinko Seiki Co., Ltd., “SW-25”), while deaerating through vacuumvents provided in the twin-screw extruder. In the evaluations below,this material is referred to as virgin material and the physical valuesof the virgin material were taken as the initial physical values.

Comparative Example 4

An attempt was made to produce a liquid crystal polyester resincomposition in a manner similar to that in Comparative Example 1, exceptthat 122 parts by mass of the glass components were blended relative to100 parts by mass of the liquid crystal polyester resin. However, theviscosity rose too high during melt-kneading and strands could not beproduced.

Production of Reground Material

Runners and sprues generated when producing the testing pieces mentionedbelow using the pellet-shaped liquid crystal polyester resincompositions in Examples 1 to 4 and Comparative Examples 1 to 3 wereground by means of a granulator (manufactured by Harmo Co., Ltd., “SPCII750H”) to obtain a reground material. In the evaluation below, thephysical values of this reground material were taken as thepost-regrinding physical values.

After hot-air drying the virgin materials and the reground materials ofExamples 1 to 4 and Comparative Examples 1 to 3 at 130° C. for 4 hours,the materials were evaluated by the methods indicated below. The resultsare indicated in Table 3 and Table 4.

Mechanical Strength Retention Rate

The mechanical strength retention rates of molded bodies formed from theliquid crystal polyester resin compositions were evaluated bydetermining the tensile strength retention rates and the Izod impactstrength retention rates.

Tensile Strength

The tensile strengths of the liquid crystal polyester resin compositionswere measured in accordance with the ASTM D638 standard, using ASTM No.4 test pieces that were produced by using an injection molder(manufactured by Nissei Plastic Industrial Co., Ltd., “PNX40-5A”) undermolding conditions such that the molding temperature was 350° C., themold temperature was 130° C. and the injection rate was 75 mm/s.

The tensile strengths of the virgin materials and the reground materialswere respectively determined, and the results obtained by calculatingthe tensile strengths of the reground materials relative to the tensilestrengths of the virgin materials were taken as the tensile strengthretention rates.

Izod Impact Strength

Measurements were made in accordance with the ASTM D256 standard, usingtest pieces that were obtained by using an injection molder(manufactured by Nissei Plastic Industrial Co., Ltd., “PNX40-5A”), undermolding conditions such that the molding temperature was 350° C., themold temperature was 130° C. and the injection rate was 75 mm/s, toproduce test pieces having a length of 127 mm, a width of 12.7 mm and athickness of 6.4 mm, then halving the test pieces in the lengthdirection.

The Izod impact strengths of the virgin materials and the regroundmaterials were respectively determined, and the results obtained bycalculating the lzod impact strengths of the reground materials relativeto the Izod impact strengths of the virgin materials were taken as theIzod impact strength retention rates.

From the results for the tensile strength retention rates and the Izodimpact strength retention rates, the mechanical strength retention ratesof the molded bodies formed from the liquid crystal polyester resincompositions were evaluated according to the criteria indicated below.

A: Tensile strength retention rate at least 90% and Izod impact strengthretention rate at least 90%

B: The above-mentioned conditions in “A” not satisfied

Heat Resistance

The heat resistances of the liquid crystal polyester resin compositionswere evaluated by determining the load deflection temperature retentionrates.

Load Deflection Temperature

Measurements were made in accordance with the ASTM D648 standard, with aload of 1.82 MPa and a heat increase rate of 2° C./min , using testpieces that were produced by using an injection molder (manufactured byNissei Plastic Industrial Co., Ltd., “PNX40-5A”), under moldingconditions such that the molding temperature was 350° C., the moldtemperature was 130° C. and the injection rate was 75 mm/s, to producetest pieces having a length of 127 mm, a width of 12.7 mm and athickness of 6.4 mm

The load deflection temperatures of the virgin materials and thereground materials were respectively determined, and the resultsobtained by calculating the load deflection temperatures of the regroundmaterials relative to the load deflection temperatures of the virginmaterials were taken as the load deflection temperature retention rates.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Liquid crystal polyester resin 55 55 5555 (A-1) [parts by mass] Liquid crystal polyester resin 45 45 45 45(A-2) [parts by mass] Glass Filler A 22.6 25 21.4 17.9 Component [partsby mass] Filler B 6.5 17.9 21.4 25 [parts by mass] Mold release agent[parts by mass] 0.3 0.3 0.3 0.3 Content [%] of first fine powder 69.874.2 83.4 84.7 Content [%] of second fine powder 3.4 3.3 0.5 3.2 Content[%] of fine powder 73.2 77.5 83.9 88.0 Diameter [μm] of fine powder 11.511.4 10.7 11.5 Number-average fiber length [μm] 280 234 252 314 of glassfibers

TABLE 2 Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Liquid crystalpolyester resin 55 55 55 55 (A-1) [parts by mass] Liquid crystalpolyester resin 45 45 45 45 (A-2) [parts by mass] Glass Filler A 42.96.5 — 122 Component [parts by mass] Filler B — 22.6 42.9 — [parts bymass] Mold release agent [parts by mass] 0.3 0.3 0.3 0.3 Content [%] offirst fine powder 12.7 97.3 93.0 — Content [%] of second fine powder 0.91.2 3.5 — Content [%] of fine powder 13.7 98.5 96.5 — Diameter [μm] offine powder 11.1 11.6 11.1 — Number-average fiber length [μm] 299 238104 — of glass fibers

TABLE 3 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Tensile virgin material 131 129 122 120strength [MPa] reground material 133 130 121 119 retention rate [%]101.5 100.8 99.2 99.2 Izod impact virgin material 450 454 441 416strength [J/m] reground material 443 444 423 398 retention rate [%] 98.497.8 95.9 95.7 Mechanical strength evaluation A A A A Load deflectionvirgin material 259 260 258 259 temperature [° C.] reground material 260259 258 259 retention rate [%] 100.4 99.6 100 100

TABLE 4 Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Tensile virginmaterial 128 121 105 — strength [MPa] reground material 120 115 92 —retention rate [%] 93.8 95.0 87.6 — Izod impact virgin material 354 441704 — strength [J/m] reground material 310 379 505 — retention rate [%]87.6 85.9 71.7 — Mechanical strength evaluation B B B mold failed Loaddeflection virgin material 257 250 221 — temperature reground material252 245 219 — [° C.] retention rate [%] 98.1 98.0 99.1 —

As indicated in Table 3, the liquid crystal polyester resin compositionsof Examples 1 to 4, in which the present invention was applied, had highmechanical strength retention rates.

This can be considered to be due to the number-average fiber lengths ofthe glass fibers having been within the range from at least 200 μm to400 μm, thus making the glass fibers less susceptible to physicaldestruction. As a result thereof, decreases in mechanical strengthcaused by the physical destruction of the glass fibers can be consideredto have been suppressed.

Additionally, it can be considered that the influence of the physicaldestruction of the glass components when reground was able to be reducedbecause the content of the fine powders relative to the total number ofthe glass components contained in the liquid crystal polyester resincomposition was within the range from at least 20% to at most 95%.

For the above reasons, the liquid crystal polyester resin compositionsin Examples 1 to 4 can be considered to have been able to raise themechanical strength retention rate when reground.

Additionally, the liquid crystal polyester resin compositions ofExamples 1 to 4 also had high load deflection temperature retentionrates. In view thereof, the liquid crystal polyester resin compositionsin Examples 1 to 4 can be considered to have excellent heat resistancewhen reground.

On the other hand, the liquid crystal polyester resin compositions ofComparative Examples 1 to 3 indicated in Table 4 had high loaddeflection temperature retention rates like those in Examples 1 to 4.Thus, they can be considered to have excellent heat resistance whenreground. However, the liquid crystal polyester resin compositions inComparative Examples 1 to 3 had low mechanical strength retention rates.

From the above results, it was confirmed that the present invention isuseful.

INDUSTRIAL APPLICABILITY

The present invention is able to provide a liquid crystal polyesterresin composition and a molded body having a high mechanical strengthretention rate when reground, and is thus extremely useful forindustrial purposes.

The invention claimed is:
 1. A liquid crystal polyester resincomposition comprising: 100 parts by mass of a liquid crystal polyesterresin; and at least 5 parts by mass and at most 100 parts by mass ofglass components; wherein the glass components contain glass fibershaving a length of more than 50 μm and glass fine powders having alength of at least 4 μm and at most 50 μm; the number-average fiberlength of the glass fibers is at least 200 μm and at most 400 μm; andthe content of the fine powders is at least 20% and at most 95% relativeto a total number of the glass components.
 2. The liquid crystalpolyester resin composition according to claim 1, wherein: the finepowders are composed of first fine powders having a length of at least 4μm and at most 40 μm, and second fine powders having a length of morethan 40 μm and at most 50 μm; and the content of the first fine powdersis at least 40% and less than 90% relative to the total number of theglass components.
 3. The liquid crystal polyester resin compositionaccording to claim 1, wherein the content of the fine powders is atleast 70% and at most 90% relative to the total number of the glasscomponents.
 4. The liquid crystal polyester resin composition accordingto claim 1, wherein the liquid crystal polyester resin containsrepeating units represented by formulas (1) to (3) below:—O—Ar¹—CO—  (1)—CO—Ar²—CO—  (2)—X—Ar³—Y—  (3) wherein Ar¹ represents a phenylene group, a naphthylenegroup or a biphenylylene group; Ar² and Ar³ represent, independently ofeach other, a phenylene group, a naphthylene group, a biphenylylenegroup or a group represented by formula (4) below; X and Y represent,independently of each other, an oxygen atom or an imino group (—NH—);and at least one hydrogen atom in the group represented by Ar¹, Ar² orAr³ may, each independently, be substituted by a halogen atom, an alkylgroup having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbonatoms;—Ar⁴—Z—Ar⁵—  (4) wherein Ar⁴ and Ar⁵ represent, independently of eachother, a phenylene group or a naphthylene group; Z represents an oxygenatom, a sulfur atom, a carbonyl group, a sulfonyl group or an alkylidenegroup having 1 to 10 carbon atoms; and at least one hydrogen atom in thegroup represented by Ar⁴ or Ar⁵ may, each independently, be substitutedby a halogen atom, an alkyl group having 1 to 10 carbon atoms or an arylgroup having 6 to 20 carbon atoms.
 5. The liquid crystal polyester resincomposition according to claim 4, wherein A¹ is a 1,4-phenylene group,Ar² is a 1,4-phenylene group and a 1,3-phenylene group, Ar³ is abiphenylylene group, and X and Y are each oxygen atoms.
 6. The liquidcrystal polyester resin composition according to claim 4, wherein: amolar ratio (3)/(1) between repeating units represented by formula (1)and repeating units represented by formula (3) is at least 0.2 and atmost 1.0; and a molar ratio (2)/(3) between repeating units representedby formula (3) and repeating units represented by formula (2) is atleast 0.9 and at most 1.1.
 7. The liquid crystal polyester resincomposition according to claim 4, wherein a molar ratio y/x betweenrepeating units represented by formula (2) is greater than 0 and at most1, wherein: x represents a molar content of repeating units in which Ar²is a 1,4-phenylene group; and y represents a molar content of repeatingunits in which Ar² is a 1,3-phenylene group.
 8. The liquid crystalpolyester resin composition according to claim 7, wherein the liquidcrystal polyester resin contains a first liquid crystal polyester resinand a second liquid crystal polyester resin, and α/β is at least 0.1 andat most 0.6, wherein: α represents the molar ratio y/x in the firstliquid crystal polyester resin; and β represents the molar ratio y/x inthe second liquid crystal polyester resin.
 9. A molded body formed fromthe liquid crystal polyester resin composition according to claim 1.